Conventionally, a motor having a speed reduction mechanism (hereinafter simply referred to as “motor with speed reduction mechanism”) is used as a drive source of a wiper device and the like to be mounted on a vehicle. The motor with speed reduction mechanism is designed so as to be a small-sized high power drive source in consideration of on-vehicle mountability. The motor with speed reduction mechanism includes a motor unit having a rotating shaft, and a gear unit having a speed reduction mechanism (such as worm and worm wheel), and is designed so that its torque is enhanced by the speed reduction mechanism by reducing rotation of the rotating shaft and a rotational force is outputted to the outside from an output shaft provided to the speed reduction mechanism.
As a motor with speed reduction mechanism which is used as a drive source of a wiper device, a motor provided with a control board for controlling the rotational direction of a rotating shaft and the number of rotations is known. As described above, a motor with speed reduction mechanism provided with the control board, for example, a motor with speed reduction mechanism disclosed in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2010-093977, FIG. 3) is known.
The motor with speed reduction mechanism disclosed in the Patent Document 1 includes a motor unit having a rotating shaft, and a speed reduction unit having a speed reduction mechanism formed of worm and worm wheel. The speed reduction unit includes a gear housing having a main body unit and a cover, the speed reduction mechanism is rotatably accommodated in the gear housing. A circuit board (control board) mounted with a plurality of circuit elements (magnetic sensor and the like) is accommodated in the gear housing, and arranged so as to cover the speed reduction mechanism in the axial direction of an output shaft.
And, the control circuit provided to the outside is configured to recognize a rotational state of the rotating shaft and the like based on a detection signal from the magnetic sensor and the like, and to control the rotational direction (positive rotation or negative rotation) and the rotational speed of the rotating shaft.